And even if at Christmas you’re all about the present – if you’ll pardon the pun – then most festive songs about the here and now don’t really cut it, either: as they’re still, really, about a Christmas we’re either hoping for or reminiscing about. I’ve lost count of the number of times I’ve heard Shaky, for example, describe the scene in which “Snow is falling / All around me” when, in fact, absolutely no snow was falling around me nor, indeed, anybody nearby.

But there is one Christmas song which talks about both the past and the future – and does so with an incredible mixture of hope and melancholy – yet which is ultimately, truly, about the present. And that’s Have Yourself a Merry Little Christmas.

Written by Hugh Martin and Ralph Blaine for their MGM musical Meet Me in St Louis, Have Yourself a Merry Little Christmas was made famous, of course, by Judy Garland. In the film, she sings it to comfort her little sister Tootie, who’s as upset as the rest of the family at the prospect of moving from St Louis to New York. Although it doesn’t quite have Garland’s desired effect – as Tootie promptly runs off and starts beheading the snowmen in the garden, in tears:

In Tootie’s defence, it’s not the chirpiest of songs to sing to someone, but that’s the beauty of Have Yourself a Merry Little Christmas. It’s not a sentimental, sugar-coated Christmas number: it’s a hopeful but truthful song which combines sadness and happiness, recognising – and thus helping us to accept – that life is a mixture of the two.

Imploring us to, yes, “have a merry little Christmas”, it tells us to let our hearts be light, adding optimistically that next year (or from now on, in some versions) “all our troubles will be out of sight”. For then – as in past, “happy golden days” – our friends will be with us once again. “Someday soon, we all will be together”, it tells us, comfortingly, before adding the caveat: “if the fates allow”. It’s no wonder that the song, introduced to the world in 1944, struck such a chord with Americans during the tragedies and uncertainties of World War II.

Life is uncertain, says Have Yourself a Merry Little Christmas – so it’s no wonder we feel uncertain, too. The penultimate line is the poignant “Until then, we’ll have to muddle through somehow” and it’s one of the most affecting lyrics in popular music, because it’s so truthful, and humane. (Frank Sinatra asked for it to be “jollied up” in 1957 – hence the “Hang a shining star” line you hear in many versions since.)

“I’ve lost count of the number of times I’ve heard Shaky describe the scene in which ‘Snow is falling / All around me’ when, in fact, absolutely no snow was falling around me nor, indeed, anybody nearby.”

We’re all muddling through somehow – at any time of year, and especially, for many of us, at Christmas time. We’re doing our best, but we’re probably also feeling imperfect, uncertain, sad or afraid. And when we’re feeling this way, one of the best things we can do – both for ourselves and others – is, as the song suggests, to concentrate on the present moment. Or to use modern parlance: to be mindful.

It may last. It may not. But let’s not worry about what may lie around the corner – or what’s gone before. Last Christmas might have been awful (especially if you were George Michael) and the next one might be wonderful (especially if you’re Shaky and you’re holidaying in the Alps). But we don’t know what the fates will, indeed, allow. So let’s make the most of what we have in the here and now. Let’s be mindful, and grateful, and stay in the moment. And do what the song’s final, most important, word reminds us to do: to have ourselves a merry little Christmas now.